Efficient bisphenol A removal by a photocatalyst-enzyme hybrid system: Horseradish peroxidase integrated with carbon vacancy-modified carbon nitride nanosheets

Peroxidase-based treatment that uses H2O2 as the clean oxidant appears promising for the removal of aqueous phenolic endocrine disrupting chemicals (EDCs). However, oxidative degradation of active heme species at high H2O2 concentrations leads to irreversible enzyme inactivation. The method of combining photocatalysis and enzyme biocatalysis could alleviate the issue by photocatalytic in-situ H2O2 production. In this study, we constructed a photocatalyst-enzyme hybrid system that integrated the horseradish peroxidase with carbon vacancymodified carbon nitride nanosheets (HRP@ACNNs). Attributed to the modified carbon nitride, the HRP@ACNNs exhibited higher substrate affinity and comparable catalytic efficiency compared to free HRP. This photocatalystenzyme hybrid system could offer H2O2 continuously to sustain enzymatic catalysis without enzyme inactivation as well as stabilize the enzyme. The bisphenol A (BPA) removal experiments further confirmed the effectiveness in treating phenolic EDCs of the prepared HRP@ACNNs.

Automated summary

In this study, a photocatalyst-enzyme hybrid system was constructed, which solved the issue of enzyme inactivation caused by high concentration of H2O2 through photocatalytic in-situ H2O2 production, and improved the stability and catalytic efficiency of the enzyme. The effectiveness of the system in treating phenolic EDCs was confirmed through experiments.